Catheter for percutaneous surgery of blood vessels and organs using radiant energy

ABSTRACT

A catheter for percutaneous surgery of blood vessels and organs using radiant energy, such as laser or radiofrequency radiation is provided, preferably for percutaneous valvotomy and for incision of membranous obstructions in vessels and hollow organs, especially in cardiac cavities. The catheter contains at least one light conductor, such as a waveguide, for EKG timed transmission of the energy radiation from its source to the point of emission of the radiation close to the distal end of the catheter. The EKG times and triggers the pulses of radiation when a heart valve is in the open position of a heartbeat. The catheter has a positioning mechanism so that the distal end of the catheter can anchor reversably and removably in a form fitting manner on a vessel or hollow organ part. The catheter protrudes into the lumen of the vessel or hollow organ part while leaving a throughput opening.

This application is based upon PCT patent application numberPCT/EP89/00005 filed Jan. 5, 1989, which is based upon German patentapplication number P 38 03 697.5-35, filed Aug. 2, 1988.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention refers to a catheter device useful forpercutaneous surgery of blood vessels and organs. The catheter usesradiant energy, such as laser high frequency or radiofrequencyradiation, preferably for percutaneous cardiac surgery, such asvalvotomy. It is also used for incision of membranous obstructions inblood vessels and hollow organs, especially in cardiac cavities. Thecatheter utilizes at least one light conductor, such as a waveguide, totransmit the energy radiation from its source to the point of emissionof the radiation at a location close to the distal catheter tip. In apreferred embodiment by means of EKG timed and triggered pulsed radiantenergy, the catheter is used to perform surgical procedures only whenthe cardiac valve is open.

2. Description of the Prior Art

Laser catheters for cardiac vessel surgery, such as is disclosed in U.S.Pat. No. 4,207,874, are being used to recanalize the interior of blockedblood vessels. Such catheters are discussed in Choy "Vascularrecanalization with the laser catheter", IEEE Journal of QuantumElectronics, No. 12, 1984, pp. 1420-1426. In this prior device thecatheter is percutaneously inserted into the blood vessel and its distaltip is advanced through the vessel up to the point of obstruction of theblood vessel caused by a thrombus or by an atherosclerotic plaque uponthe walls of the blood vessel. During subsequent removal of the blockageby laser radiation, perforation of the vessel wall can occur, if thepoint of laser emission, typically located at the distal end of cathetertip, is not properly aimed at the obstruction of plaque or if thepenetration depth of the laser light into the blood vessel exceeds thedepth of the obstruction of plaque within the blood vessel.

A device to align the point of emission in a laser catheter was proposedfor a catheter with an inflatable balloon at its distal end in U.S. Pat.No. 4,627,436 and in Nordstrom et al., "Laser angioplasty: controlleddelivery of Argon laser energy" Radiology 167, 1988, pp. 463-465)centering or otherwise directing the laser radiation emitted from thefiber. The balloon in this device, however, completely obstructs thelumen of the blood vessel. In addition, the balloon can only bepositioned in relatively narrow blood vessels and not in hollow organs,especially not in the cardiac cavity or at cardiac valves.

Furthermore, a laser catheter was employed in animal experiments toincise the septal cardiac muscle as noted in Isner et al. "The currentstatus of lasers in the treatment of cardiovascular disease", IEEEJournal of Quantum Electronics, No. 12, 1984, pp. 1406-1418). Thecatheter in Isner was inserted percutaneously and advanced to the heartof dogs under echocardiographic guidance, where upon direct contactbetween the point of light emission and cardiac muscle the incision waspossible, but selective positioning of the point of light emission at apredetermined location was not possible. Intraoperatively, a septalincision in a human heart was performed under direct vision.

From in-vitro experiments with postmortem specimen and from animalexperiments, it is also known that laser catheters can be used to ablatemembranous septum in the heart and to remove obstructions in largevessels, as noted in Riemenschneider et al., "Laser irradiation ofcongenital heart disease: Potential for palliation and correction ofintracardiac and intravascular defects", Am Heart J 106, 1983, pp.1389-1393). In the in-vitro experiments described in Riemenschneider thecatheters were directly inserted into the specimen from the outside,while a relatively nonselective perforation of the cardiac septum couldbe performed in the animal experiments using a percutaneously insertedcatheter.

SUMMARY OF THE INVENTION

The purpose of this invention is to develop a catheter device forpercutaneous surgery of blood vessels and organs using radiant energy,such as laser or high frequency radiation, which can be positionedexactly at the location of the point of operation, within the bloodvessel or organ, without interrupting blood flow and/or organ activity.

The inventive solution of the above mentioned task is provided in acatheter device, for percutaneous surgery of blood vessels and organs,which device uses radiant energy such as laser, high frequency orradiofrequency radiation. The device is used preferably for percutaneousvalvotomy surgery and for incision of membranous obstructions in bloodvessels and hollow organs, especially in cardiac cavities. The devicecontains at least one light conductor, such as a wave guide fortransmission of the energy radiation from its source to the point ofemission of the radiation nearest to the distal end of the catheter end.The catheter device has a positioning mechanism by which the distal endof the catheter can anchor itself in a removable, reversably formfitting manner upon the inner surface of a blood vessel or a holloworgan, while at the same time leaving a throughput opening within theblood vessel or hollow organ. Further preferred embodiments andvariations are noted in the following description of the preferredembodiment, as noted in conjunction with the following drawings .

The core of the invention is to equip the catheter device with apositioning mechanism which can preferably be handled by the surgeonfrom the proximal catheter end of the catheter device. The catheterdevice allows exact positioning of the device without the problems ofblood vessel obstruction, and reversable anchoring at the narrowing ofthe blood vessel or hollow organ, caused by vascular or organ parts, orother protrusions, in order to provide the necessary surgical conditionsto aim accurately the laser or other energy radiation at the targetwithin the blood vessel or hollow organ subject to incision.

According to a preferred embodiment of the invention, the positioningmechanism can be anchored on the free edge of the cardiac valve duringuninterrupted valvular activity, so that the catheter device can beemployed to open stenotic heart valves or membranous stenoses. Hereby,the laser energy radiation is EKG timed and triggered, that is, it isemitted and preferably launched into the light conductor, such as awaveguide, while the cardiac valve is open. To ensure exact aiming ofthe laser energy radiation at the intended point of incision within theblood vessel or hollow organ, such as the heart, the laser energyradiation light conductor, such as a waveguide, is at least located inthe region of the point of emission of the radiation. The lightconductor, such as a waveguide, is combined with a positioning elementof the positioning mechanism so that the point of emission of the laserenergy radiation is fixed directly at the intended target site withinthe blood vessel or hollow organ, such as the heart.

According to one preferred embodiment of the invention the positioningmechanism of the device includes at least one pair of wires, the wiresof which extend along the axis of the catheter. At the distal catheterend the wires can be spread out from a ground position closely adherentto the catheter surface to form two elastically flexible convex wirearches radially extending over the catheter surface and axiallydisplaced against each other so that an indentation is formed at theintersection of the wire arches, to anchor the catheter form fitting tothe edge of a heart valve. One or more, preferably two or three, of thewire pairs, which are made of metal or plastic, are proposed. Uponspreading, the wire pairs position themselves in the angles of thefishmouth or triangular shaped cardiac valve ostium of the heart.

In another preferred embodiment of the invention, the ends of the wirearches of each wire pair are axially displaced against each other. Theends of the wire arches are firmly attached to two preferably coaxiallyarranged catheter components, which components can be moved against eachother in axial direction. By axially shifting the catheter componentsagainst each other at the proximal end of the catheter, the wire pairsare straightened to flatly adhere to the catheter surface duringinsertion and removal of the catheter. When in use, the wire pairs arespread so that the indentation forming at the intersection between thearches anchors the catheter on the edge of a cardiac valve of the heart.This anchoring of the catheter secures the distal catheter end againstunwanted displacement.

According a modified embodiment of the invention, the wires are axiallymovable relative to the catheter and are firmly attached to the catheteronly at the distal ends of the arches of the wires.

At least one of both wires, preferably the wire forming the proximalarch of each wire pair, is combined with a light conductor, such as awaveguide, for transmission of laser radiation. The wire and the lightconductor, such as a waveguide, are arranged in parallel and arepreferably enclosed in a common coating. By placing the point ofemission of the laser light on the wire arch formed during spreading ofthe wires, a defined spatial alignment, e.g. between the point of lightemission and the edge of a valve fixed within the indentation, can beachieved to surgically incise a stenotic cardiac valve. The direction ofemitted laser radiation can be monitored continuously during thesurgical operation because the wire with the point of light emission isvisible by fluoroscopy and echocardiography, and the angle of laserradiation relative to the wire is known. In order to perform multiplesurgical incisions simultaneously or sequentially without moving thecatheter, it is useful to attach light conductors, such as waveguides,to more than one or all of the wires.

In a further preferred embodiment of the invention the point of lightemission is located and placed in the region of the indentation formedupon spreading of the wires, preferably proximal to the intersection ofthe wire arches The point of laser light emission, thereby, is in directcontact with the target site on the vascular or organ part that isanchored in the indentation of the wires of the catheter device.

In another preferred embodiment of the invention the degree of thespreading of the wire arches is variable. The spreading of the wires ispreferably adjustable using a spring, so that the wire arches remain incontact with the vessel or organ part to be incised. By means of aself-acting increase in the degree of spreading of the wire archesduring incision, the location of the point of laser light emission isadvanced until the end of the incision, so that controlled cuts ofvariable depth can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in the drawings: FIG. 1 is a side view of theproximal catheter end of the device partly in section; FIG. 2 is a sideview of the distal catheter end partly in section showing wire pairscompletely spread and partly spread; FIG. 3 is an end view of the distalcatheter end with flat wire pairs; FIG. 4 is a cross sectional view ofthe catheter along line A--A of FIG. 1; FIG. 5 is a cross sectional viewof the catheter along line B--B of FIG. 1; FIG. 6 is a cross sectionalview of the catheter along line C--C of FIG. 2; FIG. 7 is a crosssectional view of the wire combined with the waveguide.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The catheter includes two coaxially arranged catheter components 5, 6that are axially movable against each other. The inner cathetercomponent 5 is equipped with a Luer-Lok connector 11 at the proximal endand has an axially continuous lumen 20 to accommodate a guide wire 7along which the catheter is inserted. A click-stop device at theproximal end of the outer catheter component 6 arrests both cathetercomponents 5, 6 against each other when hooking into grooves 22 and 23of the catheter components. Grooves 22, 23 are located on the innercatheter component 5 in a manner that the click-stop device 8 isactivated in the two positions that correspond with the flat (c) and themaximally spread position (a) of the wire pairs as shown in FIGS. 2 and3. After release of the click-stop device 8 out of the groove 22, aspring 9 located between inner catheter component 5 and outer cathetercomponent 6 shifts the catheter components 5 and 6 axially against eachother until the wire pairs 2, 3 with their indentation 25, anchor on theblood vessel obstruction or organ part to be incised. A tube connector12 serves to flush the space between inner catheter component 5 andouter catheter component 6. An axial guide (not shown) prevents rotationof catheter components 5 and 6 against each other. Each of the coatedlight conductors, such as waveguides, 14 extend from their entry on bothsides of the proximal catheter end to the wire pairs 2, 3 at the distalcatheter end. The light conductors, such as waveguides, are coupledseparately or combined via a connector to the laser source not shown.

The metal or plastic wires 2, 3 of both partly (b) or fully (a) spreadwire pairs of the distal catheter end shown in FIG. 2 cross each other,the wires 2, 3 forming an indentation 25 which serves to position andanchor the catheter in place. The proximal ends of wires 2, 3 areaxially displaced against each other and are attached to the outercatheter component 6. The distal ends of wires 2, 3, which are alsobeing axially displaced against each other, are attached to the innercatheter component 5. Four light conductors such as waveguides 14,extend from the proximal catheter end in the wall of the outer cathetercomponent 6 and exit the surface of the outer catheter component 6,together with the wires 2, 3 to run parallel to wires 2, 3 up to thelocation of the point of light emission 4. At the location of the pointof light emission 4 each light conductor, such as waveguide, 14 and awire 2 or 3, respectively, are enclosed in a common coating 16 as shownin FIG. 7. The point of light emission 4 is constructed in a way thatthe laser radiation is emitted tangentially to the wire arch asindicated by the small arrows as shown in FIG. 2. The points ofattachment of wires 2, 3 with the inner catheter component 5 and outercatheter component 6, respectively, are reinforced with a thin metalring 13. In the ground position of both catheter components 5 and 6depicted in FIG. 3 the wire pairs 2, 3 are straight and flatly adherentto the catheter surface. The click-stop device 8, which is located atthe proximal catheter end, hooks into groove 22 in this position.

After the diagnosis of a membranous or valvular stenosis is made duringcardiac catheterization, a guide wire 7 is positioned across thestenotic valve so that the described valvotomy catheter can be insertedwith straight wires 2, 3 flatly adherent to the catheter surface. Thecatheter is then positioned in the valvular ostium so that the wirepairs position themselves in the angles of the fishmouth or triangularshaped valve ostium upon spreading, whereby the middle of the distalwire arch 3 comes to lie distal to the cardiac valve. The middle of theproximal wire arch 2 comes to lie proximal to the cardiac valve. Afterdisengaging the click-stop device 8 out of groove 22, the inner cathetercomponent 5 is shifted axially against the outer catheter component 6 bythe spring 9 spreading the wire pairs until the edge of the stenoticheart valve anchors in the indentation 25, which forms at theintersection of the wires 2, 3 upon spreading of the wire pairs.Positioning and aiming of the point of laser light emission 4 ismonitored fluoroscopically and by 2D-echocardiography. After positioningof the distal catheter end in the region of the commissures to beseparated, the points of laser light emission 4 lie in direct contactwith the target of incision, so that after coupling to the laser source,e.g. an excimer, holmium or erbium laser, the incision of the free edgeof the stenotic heart valve can commence.

The laser radiation is emitted and pushed against the targeted site onlyin the exact time interval when the cardiac valve is open, when the EKGso notes the open position of the cardiac valve and permits the laserlight to emit an incisive surgical pulse. By means of EKG timed andtriggered pulsed laser radiation, the valvotomy is performed while thecardiac valve is open. After the initial surgical incision the point oflaser light emission 4 is adjusted by means of self-acting spreading theof the wires up to the location of the end of the incision so thatcontrolled incisions of variable depth can be performed. The depth ofincision is determined on the basis of prior measurements of the cardiacvalve annulus.

I claim:
 1. A catheter for percutaneous surgery of blood vessels andorgans using radiant energy such as laser or radio frequency radiation,preferably for percutaneous valvotomy and for incision of membranousobstructions in blood vessels and hollow organs, especially in cardiaccavities comprising:at least one energy conductor for transmission ofsaid energy radiation from its source to the point of emission of saidradiation close to the distal catheter end, said catheter including apositioning mechanism by means of which said distal catheter end cananchor reversibly, removably and form fitting on one of said vessels ororgan parts, said distal catheter end protruding into the lumen of saidvessel or hollow organ while leaving a throughput opening in said vesselor hollow organ; said positioning mechanism including: at least one pairof wires, the wires of which extend substantially parallel to the axisof said catheter and said wires being spreadable at the distal end ofsaid catheter from a ground position flat and closely adherent to thesurface of said catheter, said wires forming two convex elasticallyflexible wire arches radially extending over said catheter surface, saidwires being axially displaced against each other and said wiresintersecting each other, said wires forming an indentation at theintersection of said wire arches for form fitting anchoring of saidcatheter on said vessel or organ part.
 2. The catheter according toclaim 1 wherein by means of said positioning mechanism the point ofemission of said energy radiation can be aimed at a preferred surgicaltarget located in said vessel or organ part.
 3. The catheter accordingto claim 1 wherein said light conductor for said energy radiation islocated in the region of the point of emission of said energy radiationand said light conductor is combined with a positioning element of saidpositioning mechanism that anchors on said vessel or organ part.
 4. Thecatheter according to claim 1 comprisingat least two pairs of wires,preferably arranged at equal angles to each other.
 5. The catheteraccording to claim 1 wherein said wires of each pair of wires areaxially displaced against each other at their arch ends andsaid wiresare firmly attached to two components of said catheter said componentsbeing arranged coaxially and said components being axially movableagainst each other.
 6. The catheter according to claim 1 wherein saidwires are axially movable relative to said catheter andsaid wires attheir distal ends of said arches are firmly attached to said catheter.7. The catheter according to claim 1 wherein at least one of both ofsaid wires, namely said wire forming the proximal arch of each pair ofwires carries a light conductor for laser radiation, said wire extendingsubstantially parallel and enclosed in a common coating andwherein thepoint of emission of said radiation is located in the region of saidwire arch that is formed during spreading of said wires.
 8. The catheteraccording to claim 7 wherein each wire of each said pair of wirescarries a light conductor.
 9. The catheter according to claim 7 whereinthe point of said laser light emission is located close to saidindentation formed when the said wires are spread, andsaid point oflaser light emission is proximal to the intersection of said wirearches.
 10. The catheter according to claim 1, wherein the degree ofspreading of said wires is variable.
 11. The catheter according to claim1 wherein said degree of spreading of said wires is adjustable, by meansof a spring, said wire arches remaining in contact with said vessel ororgan part to be treated by said catheter.
 12. The catheter according toclaim 1 wherein said positioning mechanism is anchorable on the valve ofa beating heart andsaid energy radiation is launched into said lightconductor by EKG trigger, while said cardiac valve is open.
 13. Thecatheter according to claim 1 wherein said positioning mechanism ishandled from the proximal end of said catheter.
 14. The catheteraccording to claim 1 wherein the light conductor is a waveguide.